On Wall Street, energy drinks are the fuel that keep trading floors going. Those in finance often keep grueling hours and energy drinks are among their favored stimulants.

It's the same with athletes, who were the first big users of energy drinks – and students, studying for exams. In fact, it's hard to think of an ambitious area of human endeavor where energy drinks or shots don't play some part.

But in recent weeks, the drinks have become an embattled choice, fueled by reports about a small number of deaths after using the drinks.

The Guardian asked readers to contribute their experiences. We heard from quite a few – good, bad, and conflicted.

Bobby Hopefield from Cornwall says he drinks the Monster energy drink at least once a day. He likes energy drinks for their sugary boost. What he has gotten instead are stomach cramps and a wariness of their addictive properties.

Jennifer Hagerty from Oxford uses coffee, caffeine pills and Red Bull for energy around exam time and to get an edge at the gym. She has felt her stomach churning, and one friend had to rest for weeks after too much caffeine.

To be honest, we'd probably be better off on Ritalin or something, but no-one's happy to take the risk.

I started drinking Relentless when I was 17 because it looked cool and boyfriend and his friends all drank it. I used to drink it to stay up to revise before exams and to get through exams. Also to stay awake for nights out. I now occasionally drink it to get through meetings at work but mostly I just drink them because I like tham and not for the effects. I love the taste of them and I get cravings for them.

Those were only a few responses from Guardian readers who shared with us their experiences of energy drinks. Some reported extreme symptoms – heart palpitations, and in one case apparent seizures.

Those responses are not completely uncommon. In the US, the Substance Abuse and Mental Health Services Administration said it found a nearly ten-fold increase in the number of emergency-room visits related to energy drinks.

Samhsa, as it is known, recorded 1,128 visits in 2005, 16,055 visits in 2008 and 13,114 visits in 2009, the most recent year for which data was publicly available.

Nearly half the emergency room visits involved alcohol or drugs being used in conjunction with the energy drinks, the agency said.

While the numbers of emergency room visits look high, they are within the context of the stratospheric growth of the energy-drink industry. For instance, while emergency room visits grew tenfold between 2005 and 2009, energy drinks as a category grew 240% between 2004 and 2009 – roughly the same period. And while those emergency room visits numbered 16,055, that same year there were 188 million cans of energy drinks sold, according to Zenith International.

And there were others who had no reaction at all, or not much.

Ben Davolls from London drinks Blue Bolt, Red Bull, and Kixx, and has coffee with one sweetener during the day. For the most part, he has not felt any ill effects, except "overdoing it on the treadmill." He is sanguine about the energy drinks.

Everything in moderation is the key – anything that sounds iffy probably is … and stay away from anything that looks like it's designed for teenagers, unless you are one.

Katlyn, a reader from Danbury, Connecticut, agrees. "I think the problem is not with the consumption and availability of energy drinks, but rather the lack of education about the risks of overindulgence and combining energy drinks with alcohol," she writes.

Obviously, drinking multiple energy drinks in a row is unhealthy and potentially dangerous, but many people don't know how harmful it can be. I am sure that if people knew more about the effects these products have on the body, they would be safer and more responsible.

Even so, many were worried that the drinks they used to get through their days and deadlines would become dangerous, and many were aware that they had become addicted, even craving the energy drinks.

Ruth Hill, a Guardian reader in Brighton, decided not to take the risks. She has an unusual job:

I compete in agility shows, which usually involve learning up to five different agility courses (of 20 obstacles each) and then running them with each of my two dogs to achieve the fastest clear round possible (competing against around 40 other dogs and handlers). I used to take Red Bull at these events because I believed it would help keep me mentally alert and give my physical energy levels a boost.

Eventually, however, she stopped.

I started to find that if I had a can in the morning and then another one in the afternoon, I would get half way around the course, then 'go blank', completely forgetting what I was supposed to do.

Now I don't touch them at all. They just seem really toxic and bad for you.

Vicky, a reader in London, says her reliance on energy drinks have caused comment among her friends, and counts her intake as one large coffee for breakfast, between one and three energy drinks in the morning and "sometimes a few more coffees":

People have expressed their concern with the amount I take. If I don't take them I am so tired I can not function. I need them to wake up, to concentrate and to feel normal … One time the shop near my work had run out of Red Bulls and I was very distressed – I knew I would not be able to work without them.

And there are others who noted positive effects from the drinks.

Alan Trinh, of London, uses an energy drink every day.

Every weekend morning, in 'preparation' for the gym, I buy a Red Bull imitation drink for 35p. I gulp it down after my porridge.

It has the same amount of caffeine in a Red Bull or a similar stimulant drink for a fraction of the price. However, Red Bull does taste a little better than the cheap stuff. But, if the milligram of caffeine is same – why not go for the cheap stuff?

As for the effects, he finds the good better than the bad. "Does it positively affect my gym performance? Yes, it does," he writes. "The 'come downs' are never enjoyable, but my workouts are always productive."

• Do you use energy drinks to stay awake at work or at school? Ever had negative side effects? Tell us in the comments below.